Follow-up electric motor control apparatus



y 1949- E. c. WAHLBERG 2,475,066

FOLLOW-UP ELECTRIC MOTOR CONTROL APPARATUS Original Filed Aug. 6, 1943 3 Sheets-Sheet l INVENTOR a; (4 mag; M45 1% July 5, 1949.

E. c. WAHLBERG FOLLOW-UP ELECTRIC MOTOR CONTROL APPARATUS 3 Sheets-Sheet 2 1 .90 92 '9' 9a 35 a4 l 33 3/0. IL loo INVENTOR 5, 1949. E. c. WAHLBERG v ,066

FOLLOW-UP ELECTRIC MOTOR CONTROL APPARATUS Original Filed Aug. 6, 1943 3 Sheets-Sheet .3

llllklr I i j g SS [I nn [I "v" u M ATTO'RNEY Patented July 5, 1949 I 2,475,066? FOLLOW-UP ELECTRIC MOTUE'CONTROL APPARATUS Eric-:0..Wahlberg, Stamford, Conn., assignor 'to Electrolux-i Corporation, Old Greenwich, .Conn., a corporation of Delaware Original application'-August 6-,"- 1943, Serial-No:-

497,600. Divided and this iapplicationf-March-L6; 1946, Serial No; 652,322

5 Claims.

gust-13 1946.

The invention :relateato an electric controller b especiallyziadapted for controllingthe operation combined speed .a-nd space control apparatus ac-,- ofsone ()I *'mOIB:'e1eGtI'iC:-IIIOtOIS' employed i fori rding -,toamyrinvention and Fi 5 an 9 dy ivjng 'n'ei nber, suchras 3,- te1esc0pe,;a, gun 011. pioded :VJ'BW 01' QI SWitCh suitable f0I-.-' use ill-GOR a searchlight which iszto be sighted. nection therewith In iaceordancewwith-myiinvention, aicont'roller 10 Re err n t -:;l, t s QW an p a elementiisi-associated with eitherr'the memberto d si nat g l y bvhereference character be rsighte'dv orva; separatesightingftelescope-"in ML} Thevairplanei comprises -.a.-.fuse1ag.e.|l having such.-armannerlasto be capable ofiimitedmovein s: fuselage mprises a; forward' ment-irelative-theretoiwhen raacomparatively light; Sealedcabin 13 a d fi pfl he C b nforce is'applied to thmelenrent. suitabieeiectricalo ISHS: provided with observation Windows I5; I61. contactsareprovidedandiarrangedso: that when a O h p ot, bomb-M01161, 211161v gun d therelement is moved?in lthesdirection.in 'WhiC'hfi tor respectively. A re V ret l8 i575 itis' desired-tomoveathemembery a circuit is coms o in the a terp lof-the fuselageh If pl eted, which;causes .opera,tion\of a,- motorsso ;a.s ;a desired, additional tlllletsix similar t0 l8 could. to-drivethe memberin the properrdirection; If 3 be. provided;beneathtthe-fuselage.and also. on.- a separate:sighting telescop'e is-emp1oyed, com thewingvsdrfaces.v Motors. l9 having.-D I pletion of; the-:circuit alsowstarts wa motor; for-J NZare-nmuntedsin the Wings-- he i pl isv driving such-.-,te1escope-, thestwo motors operating! provided'Wififi'v -2 ruddrs and injsynchljonism sg thatthemembe t be si g.hted= vators According to this invention the aile andithe sightingateiescope move'win unison As-q za rons, rudders, and-Qelevators. should be operated? the memberwith which the movablei element 'iS f by electric remote control ea s 0 y known associatedis move'dtbyitsdriving.mo-tor; the cirtyp'efr'om' Within the sealed cabinv 13. Likewise, cuitremains"- closed as :long-asvthe 1 operator 'apthe ipwpeller.pitchicha gi mechanism d plies ificiem{ m t ttle-element inthe direcenginethrottlesshould.beoperated by similar re-.- n ofsuclh! ovementttowcausestheelement to5: motecontrol'means-fromwithin-the sealed cabin. fo1iow= thememberp Whenz the-member-has'been': Rl'emotevcontrol means for-Ope a the gun 17111 moved to thevv desirediposition; relieving ithe pres-' ret I 8 from within the cabin isthe principal sub sure onthe-controller:element-opens-the circuit, je'ct ofJ'this invention andlwill-be described with} thusstopping-rthe dIii-Vi'HgmmOtOI' OIfImOtOIS; and reference to..the remaining, figures of the drawsuitable 'ibraking ymeans "preferably are 1 providedw35 in'g:

RefrringrtoiFig. 2; the-re isshown the gun di Thus; the controller in: :accordance' with the r: rectingt. apparatus zithatflis mountedimmediately. presentinventionsmayibe employed 'inasystemu below-the observationwindow I"I. A shaft 24 is foratheeremote-sightingfof-ia member; or-it may-r mountedwin end bearing 25 supported onthe; be associatedsidirectlyz-with the-member to bez io frame 26"of the fuselage. Anele'ctric-motorili sighted-i in it the vevent itisz-desired-"to drive the. also :mounted. on theframe- 2S .drives a gear: 28 member iby motive power;- rather thanmanua-llycthrough bevelrgeari 9]- Gear 28.-is supported on. Inasmuch 'asra remote-:controhsystem is more" theshaft Z iJ. ln axial alignmentwithshaft2E complicated;:myrinventionwvill-bedescribed here there.is;-a secondshtft 30 supported on gear 281: inafter in connection-withsuch'a systemin order '45 by Ia bearing, .3 la} Shaft! 30 has attached thereto V that it may be fuliyunderstood: agear 3! "and on-the upper endof-the shaft there Furthersobjectssandxadvantagesof my'invenis affi'ziedia. seatw32j An-electriomotor 33-r is: tion will.beapparent fromvthe followingzdescripe mounted/Hon the; gear. ZSJand drives gear 3h tion i considered in connection :with "the: accom--- through 'worm fi l/worm wheel 35 and .bevel gear panying-drawings which i form a part of' this r5O 36." specificationiand on which-: Fig; 1 is-a. perspec-- ThegeanSl carriesstandardswfl and-38 at the tive .iviewi ofsa rmilitary; airplane--embodying--myuppen-endshofiwhichiare hearings 39 andi 40. invention. Fi'g'swzjand 3Iare elevations, .largely Shaft Al 'carryingeitelescope or other sightingsschematic,. of.the gunrdirector' and-gunturretire device .42 is rotatably mounted in the bearings :39 spectively. Fis. 2A and'SA'are views similar to 55 Figs Zan'd 3 showingwthecorrection motorsassociated with. the gun turret. Figsmi and 5 are. Wiringidiagramsshowingthe electric circuits used in the invention. Fig. 6-isaperspective view and! Fig, Sta section. showingcertain detailsof the.

and Standard 38 supports an L-shaped stand- 3 and 43 having a bearing 46a at its upper end. Standard 43 also carries an electric motor 44 which drives a ear 45 through a bevel gear 46. Supported on the gear 45 is an electric motor 4! which drives the shaft 4I through worm 48 and Worm wheel 49. At the other end of the shaft 4| from the worm wheel 49 there is supported on a standard 31 a potentiometer 50, the moving contact 5| of which is mounted on the end of the shaft 4!. A similar potentiometer 52 is carried on a stationary part 52a of the fuselage. Its moving contact 53 is driven by the shaft 30 through bevel gears 98 and 99.

It will be apparent that as long as electric motor is at rest the electric motor 21 will drive shaft 30 at the same speed it drives shaft 24. Likewise, as long as motor 4'! is at rest, the motor 44 will drive shaft M at the same speed it drives gear 45. The motors 2'! and 44 thus serve to drive the telescopic sight 42 in azimuth and altitude respectively. The motors 33 and 41 are provided merely to introduce any necessary corrective displacement between shafts 24 and 30 and between gear 45 and shaft 4|. The purpose and operation of the corrector motors 33 and 44 will be described later. It is obvious that corrector motors 33 and 41 may be incorporated in the apparatus for driving the gun turret instead of that driving the sight. Figs. 2A and 3A illustrate the arrangement of the sight and turret when the correction motors are so arranged.

Referring to Fig. 3, there is shown the gun turret I3 which is mounted on gear 90. Gear 90 is rotatably supported on the frame 9| of the fuselage by means of an annular flange 92 cooperating with an annular groove 93 formed in the frame 9| near the outer surface of the fuselage. An electric motor 96 supported on the frame 9! drives the gear 90 through a bevel gear 97. Supported on the gear 90 are standards 94 and 95 carrying a shaft I06 in bearings at the upper end thereof. An electric motor I03 is supported on the gear 90 and drives shaft I06 through bevel gears I04 and I05. Guns I02 are mounted at either end of the shaft I06. The ends I0l of the guns project through slots I08 in the armored turret I8. The slots I08 are long enough to permit the guns I02 to move as much as needed in the vertical plane. If desired, these slots I08 may be continuous from one side of the turret to the other, providing for movement of the guns through an arc of 180 or more. A potentiometer I09 is supported inside the turret I 8. Its moving contact I I0 is carried by the end of the shaft I06. A similar potentiometer I00 is mounted on the frame 9|. The moving contact IN is driven by the electric motor 96. It will be seen that the apparatus just described provides for movement of the guns I 02 in both azimuth and altitude. The guns are driven in azimuth by motor 96 and in altitude by motor I03.

The gear ratios of the apparatus shown in Figs. 2 and 3 should be such that when motors 21 and 96 are driven in synchronism, the sight 42 and the guns I02 will be moved in azimuth through the same angle and at the same speed. Likewise, the gear ratios should be such that motors 44 and I03, when operated synchronously, will drive the sight 42 and the guns I02 synchronously in altitude. Should the main motors get out of synchronism, corrector motors 33 and 41 are automatically operated to restore synchronism between the sight 42 and the guns I02. These corrector motors are controlled by balanced bridge circuits comprising the potentiometers 50,

- supporting ring 55.

I09, 52, and I00. The gear ratios of the apparatus should be such that moving contact 5| and moving contact IIO operate synchronously as long as the sight 42 and guns I02 move synchronously in altitude. Likewise, the gear ratios should be such that moving contact 53 and moving contact IOI operate at the same speed as long as the sight 42 and guns I02 move synchronously in azimuth. Should the main drive motors get out of synchronism, the sight and guns would also get out of synchronism and likewise the positions of the moving contacts of the potentiometers. This would upset the balance of the bridge circuits and operate the corrector motors to drive the sight back into synchronism with the guns. The details of an electric circuit for carrying out this operation will be described later.

Referring again to Fig. 2, there is shown a control cylinder 54 mounted concentrically with the telescope 42. This control cylinder may be rocked slightly with respect to the telescope by movement of the handles 16 and 1'! on the ends of the handle bar 12. The details of construction of this combined speed and space control are shown in Figs. 6 and 8. As shown in Figs. 6 and 8, the sight 42 is carried by shaft M in a The supporting ring 55 is formed exteriorly with a spherical surface cooperating with spherical surface 56 on the interior of cylinder 54 to form a ball and socket support for the cylinder 54. The cylinder 54 is cut away as at 20I to permit rocking thereof with respect to the sight 42 without being hampered by the shaft 4I. Affixed to the interior of the cylinder 54 are four stationary switches 58 mounted above and below and at either side of the sight 42. These switches are of the snap action type and are operated by push buttons I50. Four more snap action switches 59 are mounted within the cylinder 54 and similarly disposed with respect to the sight 42. The switches 59 are supported within the cylinder 54 by means of springs 6|. There are studs 13 carried by the switches 59. These studs project through apertures 14 in the cylinder 54. Buttons I5 on the ends of studs "I3 limit inward motion of the switches 59. When the sight 42 is centered within cylinder 54, the push buttons '62 of the switches 59 just make contact with the exterior of the sight 42. The springs 6| are sufficiently strong to support the switches against movement when the cylinder 54 is rocked with respect to sight 42 so as to permit actuation of the switches by push buttons 62. After a push button 52 has been actuated, the corresponding springs -6I will be compressed, permitting actuation of the push button 60 of the adjoining switch 58 upon further displacement of cylinder 54 in the same direction. Springs 51 are provided for biasing the cylinder 54 into a position of axial alignment with sight 42. The end of the cylinder 54 is closed by means of a cap '63 having an opening 64 centrally thereof of sufficient diameter to permit rocking of cylinder 54 with respect to sight 42. A collar 65 formed on sight 42 provides a sliding seal for the opening 54. Either the collar is resilient or there is enough play provided to permit relative motion at this point.

In Fig. 6, there is shown the construction of the operating levers connected to the cylinder 54 for rocking it with respect to sight 42. Control lever 66 is rigidly affixed at one end to the cylinder 54 and is pivotally connected at its opposite end to handle bar 12. It will be apparent that if an operator seated on seat 32 (Fig. 3) moves both the handles 16 and TI on the ends of the handle zmaoce 51 bar 12 in the same direction either towards or away fromhimself, a motion will be imparted to the cylinder 54 rocking it with respect to sight 42' in a plane perpendicular to the shaft 41-. On the other hand,. if the operator moves one: of. the handles towards himself and the other handle away from himself, the cylinder 54 will be rocked with respect to sight 42 in the plane con. taining the sight 4% and the shaft 4t. In this arrangement the end 202 of the sight 42 is located close to the axis of the shaft til so that change in the altitude of the sight 42 will. not produce any great change inthe position of the eye piece thereof. This is. desirable so that the gun. director will not have to move his head appreciably in following a target. The: handles [6 and TI, however, are located a considerable distance below the shaft M in order to be near the operators hands. This provides a certain; leverage between the handle bars 16 and HI and the cylinder t whereby a slight pressure on the handle bars will produce sufficient motion. of the cylinder 54 to actuate one: of. the switches 58" and a slight additional, pressure without appre- :ciable movement will operate one of the switches" 53. Switches 59 operate to drive the sight and gun at one speed and switches 58 operate to drive them at a higher speeds Referring to Fig.v 7,. there is shown the internal construction of a snap action switch suitable for use in this invention. The switch comprises a casing. l8 supporting conducting plates 78 and 89. A connection. strap 8! is electrically connected to plate 19 and a similar strap (not shown) is connected to plate 8!]. Plate 86 carries a contact arm 82 which is bolted thereto at 83. Contact arm 82. carries a silver contact 84 which cooperates with a similar silver contact 2M: on plate 19 to open. and close the circuit. Two leaf springs 85 are formed on the end of the contact arm 82 and their free ends Eiltare supported in grooves 86 in the. end of plate 85; These springs are always slightly in compression, and together with contact arm- 82, form a compression toggle. A very slight movement of contact arm 32 will. cause the toggle to pass over' center and snap into closed circuit position. When the contact arm 82' is allowed to move back to its original position, the toggle will again pass over center and: snap to open position. The con-- limit inward motion of button (ill by rolling out flat on the surface of plate at- Such a switch is quite useful in the present invention because of its characteristic of operating with a snap action from open to closed position upon very slight displacement-of its push button.

In Fig. 4, there is shown a circuit diagram of the connections between the switches 58 and 59 and the main drive motors. The switches 58 and 59 mounted in one plane at either side of the sight 42 control the operation of the motors 21 and St for driving the sight and guns in. azimuth. The switches 58 and 59 mounted in a perpen-- dicular plane above and below the sight 42 con trol motors 44 and I93 for operating the sight and gunsin altitude. Sincethe connections between the switchesin one plane and their corresponding drivemotors are identicalrwith the connect-ions between the switchestin the other plane and their. corresponding drive motors,v only the 6 connections between the azimuth drive motors. and' switches have been illustrated.

Referring. again to Fig 4,. there" is shown the sight 42' and the switches 58aand 59a on one side thereof and. the switches 58b and 5% on the other side thereof. The switches 59 are supported within the cylinder 54: on springs 6t and the switches 58: are fixedly supported within the cyl inder' 54.. In: this: figure the switches are shown diagrammatically. Also shown diagrammatically are drive motors 2 1 and 9B and two relays desigimated generally by reference characters MI and I42. The system is energized' from a source 6t direct current connected to wires Ill and H2; The motors 21 and 96- are connected in parallel} across l ines I"I3= and IM. Line H3 isconnected to contacts H 5, H 6", II'I- of relay I'4I Line- IM' is connected to contacts N8 *9; and l20 oil the same relay. Motor'sz l and 96 areconstructmf as single phase rotary converters and taps are taken from fixed points on their arr-natures to slip rings- I 2Ii, i2 2, and I23, I 24 respectively. These slip-rings are connected together by wires I25? and 25 Wires-I'ZS-ahd I 2fiare'alsosuitably connected to contacts: I21 and I28 of relay I41 Power line H2 is connected to contacts" I29 I30, and? 131 power line; I-II i's-connected to con tact Hit. of. relay I4 I Also connectedto power linev I I-I- is aserlesarm'ature resistor I33 the other end of which is conr'i'ectedto contacts I 34 a-nd I 35 Relay Hi l carries" three moving contacts 204;. 205. and 286 and is operated by a solenoid I38: The center of solenoid I36 is connected to a suit able source of direct currentsuch as-bat'tery I37, the opposite side of which isconnected bywire" I38 toone contact of each of the switches 59d and 5%. The remaining contacts of these switches are connected to the opposite ends of the solenoid. I35

Battery it isalso connected by wire I39 to the actuating coil F40 of relay I421 The opposite" end of coil I40 isconnectedtoone contact of each of the switches 58a and 5825'. The" remaining contacts of these-switches are connected by wires I43 and I44- to the opposite pole of" battery I 31'.

Tllerelay I42 has moving contacts 2H1 whichare' When relay normally in open circuit position. I42 is energized; it' connects contacts I45 and I48 thereby closing a short circuit around armature resistor I33 Field" windings I41 and" I'48" ofthe motors 21* and 96 are connected" in parallel across power" lines IN and H2.

The system operates as" follows:

When the'ope'r'at'or; by pressure on the handle? bars'lt and 11 rocks the cylinder 54 with respect to eight 42- ina direction having a component in: the plane of the switches 58 and 59 controlling the azimuth drive motors 21 and 96',- one of the switches 59} say59awillbeclose'd; This will energize solenoid I36 -and cause the moving contacts ofrelay I41 to mov'e from' their rest position? tea-position one step higher. This will connecii m'o'tors 21' and 96 in parallel across lines III and" This "will energizecoil I40 M9 and 4st.

I33 to speed up the motors. If the pressure on the handle bars is reduced, the switch 58a will again open and the short circuit around resistor I33 will also be opened. This will cause the motors to slow down. If the pressure on the handle bars is completely removed, the cylinder 54 will return to its position concentric with sight 42 and the switch 59a will be opened. This will permit the relay I4I to return to the normal position shown in Fig. 4. In this position of the relay, direct current from power lines III, H2 is supplied to the tie lines I25 and I26 through contacts I32, I28 and I30, I21. At the same time contact 205 closes a short circuit across the armature-s of the motors through contacts I20, IIB. As described in applicants Patent No. 2,399,273, issued April 30, 1946, this brings the motors quickly to rest by dynamic braking while maintaining them in synchronism.

The operation of the system on movement of the cylinder 54 to close switches 58b and 59b is similar to that described for movement closing switches 58a and 59a. and need not be described in detail. The same is true of operation of the system upon movement of cylinder 54 to close the altitude control switches. It will also be apparent that upon movement of the cylinder 54 in a direction having components in both the azimuth and altitude planes the corresponding switches will be closed to actuate the azimuth and altitude drive motors simultaneously. It might be that the pressure on the handle bars I6 and II was such as to operate one set of motors at high speed while the other was operating at low speed.

Reference should now be made to Fig. 5 for a description of the operation of the corrector system. In Fig. 5, there is shown the circuit for operating azimuth corrector motor 33 upon relative displacement of the contacts 53 and IOI of the potentiometers 52 and I00. The operation of the altitude corector motor 44 is identical and hence the circuit diagram therefore has not been shown. The ends of the potentiometers 52 and I are connected by leads I53 and I54 to form a'Wheatstone bridge circuit. The bridge is energiZed by a suitable source of electric power, such as battery I55. The opposite poles of the battery are connected to the moving contacts 53 and IOI. As long as the sight and the guns are in synchronism, the moving contacts 53 and IOI will be in a position to cause balanced currents to flow through the parallel arms of th bridge circuit from the battery I55. Hence, no current flows through the coil I52 of the relay II, the coil being connected across equi-potential points in the parallel arms of the bridge circuit. Should the sight and the guns get out of step, however, such as might occur through a failure of the ties between the main driving motor-s 21 and 96, the moving contacts 53 and IOI will be angularly displaced from each other thereby unbalancing the bridge and actuating the relay I5I. The relay I5I constitutes a reversing switch for connecting corrector motor 33 across power lines The relay will connect the motor 33 in a proper manner for actuating it to bring the sight back into synchronism with the guns. If desired, the power lines I49 and I50 may be connected to the same source of power as the power lines III and H2. Th batteries I32 and I55 might also be replaced by suitable connections to this sam power supply.

From the foregoing description it will be apparent that I have provided a novel remote control system and while certain features thereof are peculiarly adapted for use in the operation of a fire control system for military aircraft, there are many features which are of general application. Furthermore, it is apparent that many modifications may be made in the preferred embodiment of the invention disclosed herein and it is intended to protect by these Letters Patent all forms of invention falling within the scope of the appended claims.

What I claim is:

1. In a device of the class described, a member to be moved, means for mounting said member for universal movement, a hollow controller movably surrounding said member and spaced radially therefrom, universal joint means disposed within said controller and outside said member for movably mounting the former directly on the latter, resilient means tending to maintain said controller centered with respect to said member, a first group of four electric switches in the space between said member and said controller, the respective switches of said first group being operable by movement of said controller in four different directions relative to said member, a second group of four electric switches in the space between said member and said controller, the respective switches of said second group being operable by a greater movement of said controller in four different directions relative to said member, electric motor means for driving said member in four different directions and at different speeds, and electric circuits for said motor means connected to said switches so that operation of any switch in said first group causes said motor means to drive said member at one speed in the same direction as the direction in which said controller was moved relative to said member to operate said switch and so that operation of any switch in said second group causes said motor means to drive said member at a faster speed in the sam direction as the direction in which said controller was moved relative to said member to operate said switch in the second group.

2. The combination as defined in claim 1 in which the switches of said first group are resiliently mounted between said member and said controller so as to be bodily displaceable by the greater movement of the controller which is required to operate the switches of said second group.

3. In a device of the class described, a member to be moved, means for mounting said member for universal movement, a hollow controller around said member and spaced radially therefrom, universal joint means disposed within said controller and outside said member for movably mounting the former directly on the latter, a plurality of electric switches in the space between said controller and said member, each of said switches being operable by a change in the dimension of said space in the locality of the respective switch, electric motor means for driving said member in different directions, and electric circuits for said motor means connected to said switches so that operation of any switch causes said motor means to drive said member in the same direction as the direction in which said controller was moved relative to said member to operate said switch.

4. In a device of the class described, a member to be moved, means for mounting said member for universal movement, a hollow controller around said member and spaced radially therefrom, universal joint means disposed within said controller and outside said member for movably mounting the former directly on the latter, a plurality of electric switches spaced circumferentially around the interior of said controller between the controller and said member, each of said. switches being operable by a reduction of the space between said controller and said member in the locality of the respective switch and all of said switches being located on the same side of said universal joint means, electric motor means for driving said member in different directions, and electric circuits for said motor means connected to said switches so that operation of any switch causes said motor means to drive said member in the same direction as the direction in which said controller was moved relative to said member to operate said switch.

5. In a device of the class described, a member to be moved, means for mounting said member so that it is pivotal in both altitude and azimuth, a first reversible motor for driving said member in altitude, a second reversible motor for driving said member in azimuth, a hollow controller around said member and spaced radially therefrom, universal joint means disposed within said controller and on the exterior of said member for movably mounting the former directly on the latter, four electric switches in the space between said controller and said member, each of said switches being operable by a change in the dimension of said space in the locality of the respective switch resultin from movement of said controller relative to said member upwardly, downwardly, to the right and to the left, respectively, and electric circuits for said motors, the circuit for said first motor being controlled by the two switches operable by up and down movement of said controller so as to cause said first motor to respectively elevate and depress said member, and the circuit of the second motor being controlled by the two switches operable by right and left movement of said controller so as to cause said second to drive said member to the right and left, respectively.

ERIC C. WAHLBERG.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS 

